Safety device for combustion chambers



Jan. 2, 1945. A. H. MAUDE 2,366,669

SAFETY DEVICE FOR COMBUSTION CHAMBERS Filed NOV. 10, 1941 a Z'f 11-- INVENTOR AY MER H. MAUDE 1o BY M Y ATTORNEY ,4

Patented Jan. 2, 1945 SAFETY DEVICE FOR COMBUSTION CHAMBERS Aylmer H. Maude, Niagara Falls, N. Y., assignor to Hooker Electrochemical Company, Niagara Falls, N. Y., a corporation of New York Application November 10, 1941, Serial No. 418,585

4 Claims. (Cl. 23-277) My invention relates more particularly to safety devices of the character known as frangible diaphragms," and has for its object to provide a diaphragm suitable for use in connection with hot corrosive gases and one which will be serviceable for a reasonable length of time and will afford complete protection under violent explosions.

The use of frangible diaphragms as a protection to containers filled with fluids under static pressure is known and practiced in cases where,

owing to the nature of the fluid, ordinary safety valves are unreliable. However, the object of my invention is more particularly to aiiord protection to reactors or combustion chambers normally under slight pressure, but in which reactions are carried on which are liable to develop explosive violence. Such a reaction is that involved in the synthesis of hydrogen chloride by combustion of hydrogen with chlorine. I This reaction is usually mild and easily controlled. However, mixtures of chlorine and hydrogen are highly explosive. Such mixtures are liable to form at the moment of ignition in starting up the process, or at any subsequent time if the fiame should become extinguished. In such a situation, unless precautions are taken, when the gases are subsequently ignited a violent explosion is liable to occur. The gases themselves then acquire such kinetic energy that they will not turn angles, but exert their force in a straight line. To be efiective therefore the frangible diaphragm must be at the end of a straight combustion chamber.

In co-pending application Serial No. 321,600, filed February 29, 1940, now Patent No. 2,295,591, of which the present application is a continuation-in-part, there is illustrated a combustion chamber of synthesis of hydrogen chloride, provided with my frangible safety diaphragm. In co-pending application Serial No. 418,586 filed of even date herewith, there is illustrated a combustion chamber of modified construction, likewise provided with phragm.

Referring to the drawing:

Fig. 1 is a sectional elevation of one combustion chamber embodying my invention, as illustrated in application Serial No. 418,586.

Fig. 2 is a plan view of this apparatus of Fig. 1.

Fig. 3 is an elevational view,. a section, of a portion of the combustion chamber, showing the frangible diaphragm of Fig. 1 to an enlarged scale.

Fig. 4 is a sectional elevation of another form my frangible safety dial of combustion chamber embodying my invention, as illustrated in application Serial No. 321,600.

Referring to Figs. 1, 2 and 3: I is'a combustion chamber, cooled by, water jacket 2 and provided at one end with burner 3 and at the other end with frangible diaphragm 4. 5 is the exit for hydrogen chloride, 6 an air vent and 1 an expansion joint in the water well of the jacket. preferably cylindrical, is adapted to be operated in a vertical position, and the cooling system, of which Jacket 2, with water connections 8 and 9, forms a part, is designed to cool the walls to within a few degrees of the dew'point of the gases, with care to avoid cooling to or below the dew point, so that the inner walls of the combustion chamber are not subjected to moist chlo- 'rine or hydrogen chloride, which of course are 10, 1941, and do not concern the present invenform of tion. Burner 3 is provided with inlets ID for chlorine and H for hydrogen. The further details of the burner are disclosed in the application referred to and likewise do not concern the present situation.

In Figs. 1, 2 and 3 the construction of the frangible diaphragm is fully illustrated. In these figures it will be seen that diaphragm 4 is clamped between annular plate l2, which closes the upper end of water jacket 2, and annular ring 13. Diaphragm 4 therefore cove'rs substantially the entire end of the combustion chamber opposite the burner. If an explosion should occur, its force would be principally in the direction in which the flame is directed, and since at the opposite end of the combustion chamber the, entire wall is formed by the. frangible diaphragm, thev chlorine and hydrogen respectively, IZA .theflange against which the frangible diaphragins are clamped and ISA the clamp rings.

Combustionchamber Lwhich is tion.

' than granularmaterial,

The details of thecooling system by which this objective is accomplished, as well as the details of the burner, are illustrated and described in parent application Serial No. 821,600, above referred to, and do not concern the present inven- In this case the burner is let in through the top wall of the horizontal cylindricalcombustion chamber, which is a side wall of the cylinder.-

'mat

The burner is, however, so formed that the combustion flame is directed longitudinally of the combustion chamber, as in the previous case.

The burner is located near one end of the com-' bustion chamber and the flame is directed toward the other end. This construction makes possible the use oi two frangible diaphragms, one at each end of the combustion chamber.

In the construction oi Fig. 4, the frangible diaphragm is of metal. However, I flnd that, since the diaphra m. ii of metal, to be eflective is necessarily very thin, and any accidental precipitation of moisture is liable to subject the diaphragm momentarily to the action of hot moist hydrogen chlorine, no ordinary metal will withstand the conditions of operation very long. In

fact, tantalum is about the only metal available for the purpose and this is very expensive. Hence in the construction illustrated in Fi s. 1 to 3 I have sought to provide a less expensive and more permanent frangible diaphragm. I have been able to accomplish this object by providing protection for the diaphragm from the extreme heat of the combustion chamber. which enables me to make use of non-metaliic,acid resistant material in its construction.

Thus, in Figs. 1 and 3 it will be seen that diaphragm 4 consists of a disc of material of the character described, clamped and forming a gasket between annular'plate l2 and annular ring ll.

I as my invention:

' 1. An apparatus for synthesis oi hydrogen chloride by burning together gaseous hydrogen and chlorine, comprising a burner for said gases housed in an elongated, gas-tight, unlined, metal walled combustion chamber, substantially symmetrical and co-axial with respect to the burner, the end of the chamber toward which the mouth oi. the burner is directed being provided with a flanged opening substantially symmetrical with respect to the axis of the chamber and adequate to relieve and protect the chamber against pressures that may develop from explosive combination of the gases; a frangible diaphragm of thin, light, flexible but relatively non-heat-resistant material, resistant however to moist hydrogen chloride, clamped against the flange of said opening and making a gas-tight closure therewith: means for cooling the walls of the chamber including the surface of the flange against which the diaphragm is seated; and a layer of light, comminuted material, resistant to heat and moist hydrogen chloride and having a large proportion of voids, loosely supported between the diaphragm and burner beyond the normal reach of the burner flame, said layer being readily expellable straight outward through said opening upon explosive rupture of said diaphragm.

2. An apparatus for synthesis of hydrogen chloride by burning together gaseous hydrogen and chlorine, comprising a burner for said gases housed in an elonga d. gas-tight, unlined, metal walled combustion chamber, substantially symmetrical and co-axial with respect to the burner, the end of the chamber toward which the mouth a of the burner is directedbeing provided with a flanged opening substantially symmetrical with 40 respect to the axis of the chamber and adequate as before stated. Beneath the diaphragm however, I provide a mat ll of material having good heat resistant and insulating properties',z;such as glass wool or fibrous asbestos. Thisis supported by a disc ii, of heat resisting material, such as sheet asbestos, which in turn rests upon lugs l8. Mat I4 is loosely packed and of slight inertia. Disc l5 rests loosely upon lugs I6. In the event of an explosion, the entire assembly consisting of disc l5, mat l4 and diaphragm 4 is projected out of the end of combustion chamber I. Lugs l6 are exposed to the heat of combustion, but as these are welded to a water cooled wall, they are suflicientlyprotected against the heat,

It will thus be seen that by the use of mat l4. as a protection for the frangible diaphragm I am able to use a diaphragm of non-metallic, acid resistantsheet material such as natural rubber or its synthetic substitutes or synthetic resins or fabric, and in particular asbestos fabric, impregnated therewith. with a combustion chamber of suitable properties and'a mat of glass wool of suitable thickness, the diaphragm need never be subjected to a temperature of over 60 0. Under these conditions a diaphragm of rubberized fabric or like material lasts many months and is found it: bedentirely satisfactory for the W innde In place of artist of fibrous material, obviously a light granular-material, such as sand, might be employed. However, fibrous material in general provides better insulation, for agiven weight,

to relieve and protect the chamber against pressures that may develop from explosive combination of the gases; a frangible diaphragm of thin, light flexible material selected from the group consisting of natural and synthetic gums and mains and textile fabrics impregnated or coated hence is to be preferred, 7s chloride,

therewith, said diaphragm being clamped against the flange of said opening and making a gas-tight closure therewith; means for cooling the walls of the chamber including the surface of the flange against whichthe diaphragm is seated; and a layer of light, comminuted material, resistant to heat and moist hydrogen chloride and having a large proportion of voids, loosely supported between the diaphragm and burnerbeyond the normal reach of the burner flame, said layer being readily expellable straight outward through said opening upon explosive rupture of said dia phragm.

3. An apparatus for synthesis of hydrogen chloride by burning together gaseous hydrogenand chlorine, comprising a burner ,for said gases housed in an elongated, gas-tight, unlined, metal the end of thechamber. toward which the mouth of the burner is directed being provided with a flanged openingsubstantially symmetrical with respect to the axis .of the chamber and adequate to relieve and protect the chamber against pressures that may develop from explosive combination of the gases; 9. frangible diaphragm of thin, light, flexible but relatively non-heat-resistant material, resistant however to moist hydrogen clamped against the flange of said'open in: and making a gas-tight closure therewith;

pellable straight outward through said opening upon explosive rupture of said diaphragm;

4. An apparatus for synthesis of hydrogen chloride by burning together gaseous hydrogen and chlorine, comprising a, burner ior said gases housed in an elongated, gas-tight, unlined, metal walled combustion chamber, substantially symmetrical and co-axial with respect to the burner, the end of the chamber toward which the mouth of the burner is directed being provided with a flanged opening substantially symmetrical with to relieve and protect the chamber against pressures that may develop from explosive combustion of the gases; a frangible diaphragm of thin, light, flexible but relatively non-heat-resistant e material, resistant however to moist hydrogen chloride, clamped against the flange of said opening and making a gas tight closure therewith; means for cooling the walls of the chamber including the surface of the fiange against which the diaphragm is seated; alayer of fibrous inorganic material adjacent the diaphragm and a sheet of rigid material loosely supported between said fibrous layer and the burner, beyond the normal reach of the burner flame, said sheet and fibrouslayer being of material resistant to heat and moist hydrogen chloride and readily expellable straight outward through said opening upon explosive rupture of said diaphragm.

respect to the axis or the chamber and adequate 20 AYLMER H. MAUDE. 

